Blue Shifting of Hydrogenated Silicon Carbide Multiple Quantum Wells

Five-period hydrogenated silicon carbide (SiC) multiple quantum wells with silicon dioxide (SiO2) or silicon nitride (SiN) dielectric that were synthesized by high density plasma chemical vapor deposition were studied using photoluminescence (PL) spectroscopy to understand its blue shift. Rapid thermal annealing induced significant blue shifting in the PL spectra after fluorine ion implantation due to crystallization. The thinning of the SiC causes blue shift due to the quantum confinement effect. The higher PL intensity of the amorphous SiC:H in SiO2 than in SiC/SiN may be attributed to the high number of non-radiative sites on its surface. Annealing with nitrogen may cause impurities in SiC/SiO2, thereby broadening the PL peak.

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UV Emission Mechanisms in Quaternary AlInGaN Epilayers and Multiple Quantum Wells

MRS Proceedings ◽

10.1557/proc-722-k1.7 ◽

2002 ◽

Vol 722 ◽

Author(s):

Mee-Yi Ryu ◽

C. Q. Chen ◽

E. Kuokstis ◽

J. W. Yang ◽

G. Simin ◽

...

Keyword(s):

Quantum Wells ◽

Light Emitting Diode ◽

Chemical Vapor ◽

Excitation Power ◽

Multiple Quantum Wells ◽

Multiple Quantum ◽

Excitation Power Density ◽

Light Emitting ◽

Uv Emission ◽

Alloy Disorder

AbstractWe present the results on investigation and analysis of photoluminescence (PL) dynamics of quaternary AlInGaN epilayers and AlInGaN/AlInGaN multiple quantum wells (MQWs) grown by a novel pulsed metalorganic chemical vapor deposition (PMOCVD). The emission peaks in both AlInGaN epilayers and MQWs show a blueshift with increasing excitation power density. The PL emission of quaternary samples is attributed to recombination of carriers/excitons localized at band-tail states. The PL decay time increases with decreasing emission photon energy, which is a characteristic of localized carrier/exciton recombination due to alloy disorder. The obtained properties of AlInGaN materials grown by a PMOCVD are similar to those of InGaN. This indicates that the AlInGaN system is promising for ultraviolet applications such as the InGaN system for blue light emitting diode and laser diode applications.

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Epitaxial Growth and Characterization of Nonpolar A-Plane AlGaN-Based Multiple Quantum Wells

Materials Science Forum ◽

10.4028/www.scientific.net/msf.934.8 ◽

2018 ◽

Vol 934 ◽

pp. 8-12

Author(s):

Jian Guo Zhao ◽

Xiong Zhang ◽

Jia Qi He ◽

Shuai Chen ◽

Zi Li Wu ◽

...

Keyword(s):

Quantum Wells ◽

Chemical Vapor ◽

Multiple Quantum Wells ◽

Modulation Method ◽

Duty Ratio ◽

Organic Chemical ◽

Multiple Quantum ◽

X Ray Diffraction ◽

Metal Organic

A serious of non-polar a-plane AlGaN-based multiple quantum wells (MQWs) were successfully grown on the semi-polar r-plane sapphire substrate with metal organic chemical vapor deposition technology. Intense MQWs-related emission peaks at an emission wavelength covered from 277-294 nm were observed based on the photoluminescence measurement. It was found that the employment of the trimethyl-aluminum (TMAl) flow duty-ratio modulation method which was developed based on the two-way pulsed-flows growth technique played a crucial role to control the Al composition of the non-polar a-plane AlGaN epi-layers. The non-polar a-plane AlGaN-based MQWs were deposited with the new developed TMAl flow duty-ratio modulation technique. Evident-3th order X-ray diffraction (XRD) satellite peak was observed from the high resolution-XRD measurement, proving the successful growth of non-polar a-plane AlGaN-based MQWs with abrupt hetero-interfaces.

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TEMPERATURE DEPENDENCE OF PHOTOLUMINESCENCE OF FLAT AND UNDULATED SiGe/Si MULTIPLE QUANTUM WELLS

International Journal of Modern Physics B ◽

10.1142/s0217979202015108 ◽

2002 ◽

Vol 16 (28n29) ◽

pp. 4211-4214 ◽

Cited By ~ 3

Author(s):

B. W. CHENG ◽

J. G. ZHANG ◽

Y. H. ZUO ◽

R. W. MAO ◽

C. J. HUANG ◽

...

Keyword(s):

Elevated Temperature ◽

Quantum Wells ◽

Blue Shift ◽

Band Alignment ◽

Multiple Quantum Wells ◽

Luminescence Spectra ◽

Multiple Quantum ◽

Type Ii ◽

Thermally Activated ◽

Strained Sige

Photoluminescence (PL) of strained SiGe/Si multiple quantum wells (MQW) with flat and undulated SiGe well layers was studied at different temperature. With elevated temperature from 10K, the no-phonon (NP) peak of the SiGe layers in the flat samples has firstly a blue shift due to the dominant transition converting from bound excitons (BE) to free excitons (FE), and then has a red shift when the temperature is higher than 30K because of the narrowing of the band gap. In the undulated sample, however, monotonous blue shift was observed as the temperature was elevated from 10 K to 287 K. The thermally activated electrons, confined in Si due to type-II band alignment, leak into the SiGe crest regions, and the leakage is enhanced with the elevated temperature. It results in a blue shift of the SiGe luminescence spectra.

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